Modelling for Unity, should I remove intersecting parts?
If the pieces are two seperate objects, press Ctrl + J to join them, that is better for performance, because it reduces the drawcalls from 2 to 1. If the pieces are one object with two intersecting pieces, this is fine, in fact, it is better than wasting resources rendering hundreds of faces when you just need 10. Sure, if you zoom in really, really far, the intersection won't look too pretty, but how often do zoom that far in on the roof of a house?